Woodward UG-8 Governor 8522-547

Woodward UG-8 Governor P/N 8522-547 (700–1415 RPM)

The Woodward UG-8 (Dial Type) Part Number 8522-547 is a mechanical-hydraulic governor engineered for precise speed and load control of marine diesel engines, auxiliary generator sets, and industrial turbines. Operating on an integrated hydraulic servo system, the governor utilizes a spring-driven, oil-damped ballhead and flyweight mechanism counterbalanced by an internal speeder spring.

This specific configuration provides an operating drive range calibrated for 700 to 1415 RPM, producing a maximum mechanical output of 8 ft-lb (10.8 N·m) over a 42° terminal shaft rotation (recommended effective working travel is 28° delivering 5.3 ft-lb). The dial control panel provides local synchronization, mechanical speed setting, mechanical load limiting with an integrated fuel rack shutdown cam, and adjustable droop for parallel generator operation.

Key Features

1. Isochronous & Droop Modes: Supports true zero-droop constant speed regulation or proportional droop adjustable up to 19% for multi-engine load sharing.
2. Mechanical Load Limit & Stop: Front dial manual load limiter allows mechanical indexing of fuel rack stops and quick engine trip via the zero mark.
3. Damped Centrifugal Flyweight System: Features hydraulic dashpot compensation with adjustable needle valve to eliminate speed oscillations and hunting.
4. Bi-Directional Internal Gear Pump: Symmetrical four-check-valve pump architecture charges internal accumulators to 120 PSI under clockwise or counterclockwise drive.
5. Zero External Hydraulics Required: Independent, self-contained oil sump avoids contamination from prime mover lube oil systems.

Compatible Prime Movers

• Medium-Speed Marine Auxiliary Diesel Engines: Daihatsu (DK, DC series), Yanmar (M200, EY18, S185, N165), Wärtsilä / Sulzer (S20, AL20), MAN B&W Holeby (L23/30, L28/32).
• Industrial & Heavy Engines: Caterpillar 3500/3600 Series, EMD 645/710, Fairbanks Morse 38D8-1/8, Bergen K-series.
• Mechanical Drive Steam Turbines: Terry, Coppus, and Elliott mechanical-drive units within rated RPM limits.

Industrial & Marine Applications

• Shipboard diesel generator sets (synchronous 50 Hz / 60 Hz prime power generation).
• Main propulsion variable-speed prime mover control.
• Fire pump, dredge pump, and cargo booster pump engine governors.
• Off-grid municipal and marine industrial standby generation systems.

Part Number Cross-References

• Woodward Dial Governor Base Part Number: 8522-547
• Equivalent / Alternate Variants: 8522-447, 8524-309, 8524-708, 8525-015, 8526-425, 8527-162
• OEM Technical Manuals: Woodward Manual 03040 (UG-8 Dial Models), Manual 03029 (UG-8 Governor General Specifications), and Manual 54042 (Linkage & Mounting Instructions).

Frequently Asked Questions

What causes a Woodward UG-8 governor to “hunt” or surge continuously?

Governor hunting is typically caused by trapped air inside the hydraulic passages, incorrect compensation needle valve settings, or fouled internal oil. Bleeding the compensation valve while fluctuating the terminal linkage usually eliminates air. If instability persists, verify that the drive shaft quill gear is not worn.

Can the UG-8 8522-547 be converted between clockwise and counter-clockwise drive rotation?

Yes. The internal gear pump is equipped with four automatic spring-loaded check valves, allowing internal oil pressure generation regardless of input rotation direction.

What is the difference between an isochronous and droop speed setting on the UG-8?

Setting the droop knob to zero forces the governor to run isochronously, holding exact speed regardless of engine load. Increasing droop causes engine speed to slightly decrease as electrical or shaft load rises, which is necessary when paralleling two or more alternators on a shared marine switchboard.

How do I mechanically shut down an engine equipped with a UG-8 Dial governor?

Rotate the front Load Limit knob counter-clockwise to position 0. This engages an internal shutdown lever that overrides the pilot valve plunger, dumping oil from under the servo piston and forcing the output shaft to the zero-fuel position.